Weak M - H⋯H - C interactions observed in ruthenium and iridium complexes containing hydride, amine, and bulky phosphine ligands

Abstract

New amineruthenium and amineiridium hydride derivatives have been synthesized and characterized with the objective of observing intramolecular MH⋯HN or MH⋯HO interactions. These include RuHCl(CO)(L)(PPrj3)2 (1a, L = NH2NH2; 1b, L = NH3) and IrCl2(L)(H)(PCy3)2 (2a, L = SC(NH2)2; 2b, L = NH3; 2c, L = NH2NH2; 2d, L = NH2(CH2)3NH2; 2e, L = NH2OH). Instead, weak M - H⋯H - C van der Waals contacts have been detected in the solid state by X-ray analysis and in solution by NMR T1 measurements and nOe techniques. Both X-ray crystal structure analysis and minimum T1 measurements indicate that the H⋯H distances in the M - H⋯H - C interactions are ca. 2.0-2.2 Å. The weak interactions might influence the course of deuteration of these complexes under D2 gas. The crystal and molecular structure of IrCl2(NH3)(H)(PCy3)2 2a has been determined by X-ray diffraction at 173 K: monoclinic, space group P21/n, a = 14.859(2) Å, b = 18.579(3) Å, c 7 18.548(3) Å, β = 97.29(1)°, V = 5079.1(13) Å3, Z = 4, full-matrix least-squares refinement on F2 for 10 953 independent reflections; R[F2 > 4σ(F2)] = 0.0283, wR(F2) = 0.0704.